Dr. Stefan is an academic hospitalist at Baystate Medical Center and an Assistant Professor of Medicine at the Tufts University School of Medicine in Boston, MA. Her goal is to become an independent clinician scientist focused on applying rigorous research methods to the identification and implementation of effective treatment strategies for patients hospitalized with respiratory disease. The proposed career development plan incorporates advanced training in epidemiology, clinical trials, and implementation and dissemination research as part of a PhD in Clinical and Translational Science, as well as a closely mentored research experience. Dr. Stefan has assembled a group of highly skilled mentors who will guide her development. Dr. Lindenauer, the primary mentor, has significant mentorship experience, and is an accomplished investigator currently supported through RC2 and R18 awards from NHLBI to study outcomes in patients with COPD, as well as R18 funding from AHRQ. Dr. Stefan works within a supportive research environment that has an established track record of success and experience mentoring investigators toward independent research careers. In 2009, Acute Respiratory Failure (ARF) was associated with 1.9 million hospitalizations in the US and accounted for approximately 320,000 deaths and more than $50 billion dollars in hospital spending. Given its enormous impact and high associated mortality there is a critical need for research efforts focused on identifying interventions to improve the outcomes of patients with ARF. In this career development award Dr. Stefan will perform a retrospective observational study of patients with ARF in a large registry of more than 100 hospitals throughout the US using clinical data derived directly from the hospitals' electronic medical records. The specific aims of this project are: 1) to characterize current ventilation management practices in ARF and identify patient and hospital factors associated with the choice of ventilation therapy; 2) to compare the effectiveness of noninvasive and invasive forms of mechanical ventilation in patients hospitalized for the most common causes of ARF; 3) to identify predictors for noninvasive ventilation success/failure. To limit the threat of confounding she will employ diverse and powerful analytical methods including logistic regression, high- dimensional propensity technique, and instrumental variable approach. This research speaks directly to the NHLBI Strategic Plan Goal III: To generate an improved understanding of the processes involved in translating research into practice and use that understanding to enable improvements in public health and stimulate further scientific discovery. It is also responsive to the AHRQ Comparative Effectiveness Review on NIV in ARF which highlights the paucity of comparative effectiveness studies and the limited data for patients with ARF not due to COPD or cardiogenic pulmonary edema.